Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013
Statement of Stockholders' Equity [Abstract]
Dividends per common share (in dollars per share)	$ 0.07	$ 0.07	$ 0.07	$ 0.07	$ 0.0625	$ 0.0625	$ 0.0625	$ 0.0625	$ 0.0575	$ 0.0575	$ 0.0575	$ 0.0575
Dividends per preferred share (in dollars per share)	$ 20.00	$ 20	$ 20	$ 20	$ 20	$ 20	$ 20	$ 20	$ 20.00	$ 20	$ 20	$ 20